Now videos circulating on social media are showing kids biting into brightly colored liquid laundry detergent packets. Or cooking them in frying pans, then chewing them up before spewing the soap from their mouths.

On Wednesday, YouTube said it would "work to quickly remove flagged videos that violate our policies," spokeswoman Jessica Mason said in a statement.

“YouTube’s Community Guidelines prohibit content that’s intended to encourage dangerous activities that have an inherent risk of physical harm."

It’s not certain how the Tide pod fad got started.

The U.S. Consumer Product Safety Commission issued a warning to parents several years ago about the liquid laundry detergent packets. The agency said the capsules — which are colorful, squishy and smell good — are attractive to young children but contain “highly concentrated, toxic detergent” that can cause harm.

In 2015, the Onion published a satirical op-ed from the perspective of a toddler who wanted to eat them.

At some point, the pods became alluring to older children. Last year, College Humor published a video titled “Don’t Eat the Laundry Pods. (Seriously. They're Poison.).” It showed a college student researching the dangers associated with exposure to the packets, then devouring them. He ended up on an ambulance stretcher.

One expert conceded that young children are inclined to explore but was surprised at the number of older children and teenagers who are putting the packets in their mouths.

Last year, U.S. poison control centers received reports of more than 10,500 children younger than 5 who were exposed to the capsules. The same year, nearly 220 teens were reportedly exposed, and about 25 percent of those cases were intentional, according to data from the American Association of Poison Control Centers.

So far in 2018, there have been 37 reported cases among teenagers — half of them intentional, according to the data.

“A lot of people were just saying how stupid I was or how — why would I be willing to do that?” 19-year-old Marc Pagan, who said he was dared to do it, told CBS News last week. “No one should be putting anything like that in their mouths, you know?”

Children who have been exposed to the capsules have been hospitalized with vomiting, breathing difficulties and loss of consciousness. And the consequences may be much worse. Since 2012, eight fatalities have been reported among children 5 and younger, according to the American Association of Poison Control Centers.

Aleguas, Florida Poison Information Center, said that as with nearly any substance, “the dose makes the poison.”

The laundry detergent packets pose two potential problems, he said. Children and teens can aspirate on the liquid by inhaling it into their lungs, or they can become ill by ingesting it — experiencing a change in blood pressure and heart rate, losing consciousness or having seizures.

And because many teens may not have had the need for a thorough physical exam, Aleguas said, some may not know they have underlying medical conditions, such as asthma, that could put them at a higher risk for complications.

Tide's parent company, Procter & Gamble, said in a statement that it is “deeply concerned about conversations related to intentional and improper use of liquid laundry pacs.”

“Laundry pacs are made to clean clothes,” Proctor & Gamble spokeswoman Petra Renck said in the statement. “They should not be played with, whatever the circumstance, even if meant as a joke. Like all household cleaning products, they must be used properly and stored safely.”

In response to nationwide headlines late last week about the “Tide pod challenge,” the company released a public service announcement on social media, featuring the New England Patriots' Rob Gronkowski discouraging people from playing around the laundry detergent packets.

“What should Tide PODs be used for? DOING LAUNDRY. Nothing else,” the company said on social media. “Eating a Tide POD is a BAD IDEA, and we asked our friend @robgronkowski to help explain.”

To report exposure to laundry detergent pods, call the national poison hotline at 1-800-222-1222 or text POISON to 797979 to save the number on your phone.

Lindsey Bever is a general assignment reporter for The Washington Post, covering national news with an emphasis on health.